| Simon Glass | 29db946 | 2020-04-08 16:57:32 -0600 | [diff] [blame] | 1 | * HID over I2C Device-Tree bindings |
| 2 | |
| 3 | HID over I2C provides support for various Human Interface Devices over the |
| 4 | I2C bus. These devices can be for example touchpads, keyboards, touch screens |
| 5 | or sensors. |
| 6 | |
| 7 | The specification has been written by Microsoft and is currently available here: |
| 8 | http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx |
| 9 | |
| 10 | If this binding is used, the kernel module i2c-hid will handle the communication |
| 11 | with the device and the generic hid core layer will handle the protocol. |
| 12 | |
| 13 | Required properties: |
| 14 | - compatible: must be "hid-over-i2c" |
| 15 | - reg: i2c slave address |
| 16 | - hid-descr-addr: HID descriptor address |
| 17 | - interrupts: interrupt line |
| 18 | |
| 19 | Additional optional properties: |
| 20 | |
| 21 | Some devices may support additional optional properties to help with, e.g., |
| 22 | power sequencing. The following properties can be supported by one or more |
| 23 | device-specific compatible properties, which should be used in addition to the |
| 24 | "hid-over-i2c" string. |
| 25 | |
| 26 | - compatible: |
| 27 | * "wacom,w9013" (Wacom W9013 digitizer). Supports: |
| 28 | - vdd-supply (3.3V) |
| 29 | - vddl-supply (1.8V) |
| 30 | - post-power-on-delay-ms |
| 31 | |
| 32 | - vdd-supply: phandle of the regulator that provides the supply voltage. |
| 33 | - post-power-on-delay-ms: time required by the device after enabling its regulators |
| 34 | or powering it on, before it is ready for communication. |
| 35 | |
| 36 | Example: |
| 37 | |
| 38 | i2c-hid-dev@2c { |
| 39 | compatible = "hid-over-i2c"; |
| 40 | reg = <0x2c>; |
| 41 | hid-descr-addr = <0x0020>; |
| 42 | interrupt-parent = <&gpx3>; |
| 43 | interrupts = <3 2>; |
| 44 | }; |